Make CI build to use optimistic locking only on status change

Merged Kamil Trzciński requested to merge optimistic-locking-ci-status-change into master

What does this MR do?

We update Ci::Build often, what matters for us is to only lock build when there is status change.

Does this MR meet the acceptance criteria?

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/29679